Geography
How Population Dynamics Shape Urban Planning and Infrastructure Investment
Quick fact
A city's infrastructure—roads, schools, water pipes—is built to last 30 to 100 years, but population forecasts can swing by millions in a decade. Even a single large migration wave can overrun a city's capacity, while a sudden downturn leaves it with half-empty neighborhoods and costly maintenance bills.
Why this is interesting
You might think cities are built for the people who live in them today—but they are actually designed for the people who will live there decades from now. How do planners predict who will come, and what happens when they get it wrong?